Modern advanced photocopying apparatus are extremely sophisticated, and machines currently available are able to produce very high quality images and provide a great variety of functions. In basic terms, such a machine comprises a high quality scanner and a high quality printer, in combination with a dedicated computer operable in response to user input commands and preset protocols. In common with the most basic photocopying equipment, though, a problem remains that deterioration of copy quality will inevitably occur as successive generations of copies are made from an original document.